The present invention deals with a device for controlling an internal combustion engine of a motor vehicle. More particularly, it relates to a device for controlling the internal combustion engine of a motor vehicle which has a sensor system with a transducer wheel having on its circumference a plurality of segments proportional to the number of cylinders of the engine, and a stationary pickup element which is affected by the segments of the transducer wheel and provided with a control circuit for ignition or the like of the motor vehicle
In a devices for controlling an internal combustion engine of a motor vehicle, in particular for controlling its ignition and the like, it is known to use sensor systems for detecting the angular position of an shaft, in particular the crank shaft or the camshaft.
Such systems are embodied as segmental systems, for example, in which transducer wheels rotate with the shaft and are provided on their circumference with a number of segments, that is, elongated marked zones, that is proportional to the number of cylinders in the engine. For detecting the angular position of the crankshaft, the number of segments is one-half the number of cylinders. For detecting the angular position of the camshaft, the number of segments equals the number of cylinders, because as is well known, the crankshaft rotates at twice the speed of the camshaft. Each segment is correlated with one cylinder (or in the case of detection of the crankshaft, with two cylinders) of the engine, and each ignition event is controlled as a function of the travel past it of the associated segment. The leading edge of the segment is recognized in a stationary pickup element, and the control events for the engine are triggered by suitable timing control over the entire length of the segment. Segmental systems having segments of equal size have the disadvantage, by comparison, that it is impossible to correlate the segments properly for a distributorless or dual-circuit (in an eight-cylinder engine, for example) high-voltage distribution.
Segmental systems are also known in which individual segments are divided into a number of teeth and tooth gaps, and the signals generated in the pickup element by the teeth or tooth gaps are supplied to a control circuit. The angular position of the shaft is ascertained by counting the teeth or tooth gaps traveling past. This method is complicated and requires an extra counting device.
Also, if only a single tooth gap is formed in one segment, then there is the danger that the aditional trailing edge will trigger an additional ignition.
In all the devices discussed above, recognition of an accurate correlation of the marking requires at least one rotation upon startup of the engine.